


split second traversal

by Anonymous



Category: Naruto, 僕のヒーローアカデミア | Boku no Hero Academia | My Hero Academia, 呪術廻戦 | Jujutsu Kaisen (Manga)
Genre: Alternate Universe - Canon Divergence, Alternate Universe - Twins, Crack Crossover, Crack Treated Seriously, Dimension Travel, Gen, giving the cast of bnha a migraine one troll at a time, kaksshi and gojo are trolls
Language: English
Status: In-Progress
Published: 2021-02-15
Updated: 2021-02-18
Packaged: 2021-03-17 08:55:27
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 2,577
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29469063
Author URL: https://archiveofourown.org/
Summary: The last of the nurses to leave whose head was a literal lego block closes the door to their room to give them some privacy.“A different world?” Kakashi asks, blinking almost bemusedly.“A different world!” Satoru agrees, clapping his hands in delight.
Relationships: Gojo Satoru & Kamihara Shinya | Edgeshot, Hatake Kakashi & Gojo Satoru, Hatake Kakashi & Kamihara Shinya | Edgeshot
Comments: 40
Kudos: 329
Collections: Anonymous





	1. Chapter 1

**Author's Note:**

> hahah kakashi and gojo go brrrrrr

Shinya’s brothers - and they’re definitely his brothers, there’s absolutely no doubt about it - look up at him with twin looks of confusion.

Or at least one of them is. 

“Woah,” Satoru says, wild silver - almost white - hair standing up like the leafy ends of a scallop, secured with an honest to god _blindfold_ over his eyes, “You’re us but bigger.”

When he’d gotten a call from Musutafu’s general hospital after just finishing his internship, he hadn’t expected to see two carbon copies of him along with a woman who was most likely from the social services.

Shinya blows an amused huff through his nose, “I _am_ your brother.” He says to the two children.

The youngest hums thoughtfully, tapping his index finger on his chin, “True,” He then curls his eyes into an upside down U, “Maa...nice mask.”

Shinya’s lips twitched into a small smile from underneath the stretch of fabric on his face and neck, “Thanks. I like yours too.” He laughs when Satoru crosses his arms and pouts.

Gang Orca looks at the three Kamiharas, their silver hair and then the mask they all seemed to wear, and wheezes, “Oh god it’s _hereditary_?”

* * *

Nothing beats a traumatic backstory to kickstart your second lease at life. 

For the Kamihara twins, it starts with an alcoholic, a gambler, one unfortunate argument after too many and two tumbles down the stairs head first onto the solid ground. There’s two distinct cracks, four pairs of limbs tangled at the foot of steps and then complete and utter darkness.

The next time they awakened, one of them was sporting eyes that seemed to fracture into spectral patterns and the other one had pinwheels swimming in an ocean of red. The blue-eyed boy reaches up to his forehead, startles when his hand meets nothing but his skin, and then starts tearing up. His crimson-eyed counterpart does a similar gesture, only instead of his forehead, he was touching his bare face with a look of abject horror.

“My mask!” They cry, and the nurses would find it cute if they didn’t sound so heartbroken about it. 

In an attempt to calm the two kids down, one of them approaches their bed and asks, “Why do you need your masks?”

Satoru - the older twin - turns to them and says, “My eyes are too pretty for you!” before immediately sobbing into more uncontrollable tears.

His younger twin - Kakashi - looks all too serious despite the stray tears that roll down his chubby face as he whines softly, “I was hiding my b-buck _tootsies_.” 

The unanimous decision was to conduct a few more additional exams. Head injuries are serious after all, especially on children as young as these two.

* * *

Their stare-down after they were left to their own devices lasts only for a couple of seconds. The last of the nurses to leave whose head was a literal lego block closes the door to their room to give them some privacy.

They both come to a very distinct conclusion.

“A different world?” Kakashi asks, blinking almost bemusedly. 

“A different world!” Satoru agrees, clapping his hands in delight.

“Neat.” Kakashi says, not even questioning what his life was anymore. Obito and the rest can wait at the Pure Lands. Right now, he’s going to bury himself in this nice bed and get some damn _sleep._

The other boy follows his lead and plops down next to him, staring at Kakashi with barely concealed curiosity. Kakashi, feeling much better with a medical mask on his face, blinks at him in question.

Meanwhile Satoru, with almost three decades underneath his belt, curses pressed against his skin and infinity thrumming between him and the rest of the world takes one look at the other boy, catches the familiar glint of trauma in his red eyes, and then smiles knowingly. 

“Hi,” He says, lips stretching wide, “I’m Satoru. I’m your brother, but I’m also not anymore!”

Kakashi, with the legacies of three separate Clans etched into his skull, reflected on his face and tattooed as a time seal on the nape of his neck, blinks Obito’s two red eyes, tilts his head and offers an eye smile.

“Hi,” He says back, wiggling his fingers in a wave from underneath their thin sheets, “I’m Kakashi. I used to be a ninja.”

Satoru’s blue eyes widened in excitement, shuffling closer until they were almost nose to nose on their bed.

“Like - like the ones that throw stars and kunai and move in the shadows and stuff?” He whispers almost conspiratorially.

Kakashi nods, “Yeah. What about you?”

Satoru blinks and his really, really long eyelashes flutters slowly in response. Kakashi's almost surprised to see ones that are as long as his.

“I used to exorcise cursed spirits,” He says, “They called me the strongest sorcerer you know?”

Kakashi makes a sound of interest, “Cool,” He hears footsteps outside their door, tenses, and then relaxes when they walk past their room. Satoru was looking at him with a purposeful stare, “Did you die too?”

His now brother’s face scrunches, “I can’t die so they sealed me away,” He says, and then adopts a more thoughtful look, “But I didn’t want to be sealed so I tried one last technique and then I woke up here.”

“Oh.” Kakashi murmurs, wondering why the other can’t die.

“It’s hard to get close to me,” Satoru answers when Kakashi asks about it, “There’s me and then there’s the infinity between you and me.” He holds out his hand and urges Kakashi to hold it. Kakashi obliges and jumps when his movement slows down, almost like an invisible barrier was separating them, “I see everything.”

_How useful_ , Kakashi thinks, _And insanely overpowered_. 

“Is that why your eyes are like that?” He asks again. Satoru nods, humming a pleased affirmation behind his throat.

“Yeah! It helps me control and distort space,” His nose twitches, “It’s really complicated. I can explain better when my brain isn’t mushy.”

“That’s okay,” Kakashi tells him, clumsily patting his hand in reassurance, “We have time.”

Satoru looks surprised, although he does tilt his head as he stares at Kakashi’s own red ones.

“What does yours do?”

At this, Kakashi grins, “Control space and time.”

Satoru’s answering squeal makes him giggle.

  
  



	2. Chapter 2

**Summary for the Chapter:**

> Satoru makes a new friend. Kakashi naps away

**Notes for the Chapter:**

> thank you so much for the kudos and comments guys!! here’s a silly chapter that i hope you enjoy!

“Who stole my kikufuku.”

Ryuko looks up from her laptop and watches as Yawara stomps from their kitchen to the living room. Her classmates - or the ones that were present anyways, Hirabayashi, Ieyasu, and Shimizu-chan - who’d been ignoring their homework for the past twenty minutes in lieu of watching a compilation of cat videos, make various noises of confusion.

Yawara’s levels of _intimidating_ are pretty mellow on his good days but he looks like he’s one puff of breath away from flipping a table.

“My. Kiku. _Fuku_ ,” He grits out. Ieyasu scrambles back with a squeak and ducks behind Shimizu, who shoots him an amused stare, “It’s gone. All of it. _Who ate it_.”

“Ah...Not me?” Hirabayashi pipes up, nervously grinning, “As far as I’m aware anyways.”

Shimizu shakes her head and signs, _I didn’t touch your sweets either, Chatora-san_ _._

Ryuko huffs when Yawara shifts his glare towards her, “You know I don’t touch your things without asking!”

They all swivel to Ieyasu who was cowering pathetically from where he’d taken refuge behind an eternally patient Shimizu.

“W-What?” He stutters, paling as Yawara advances towards him, “Okay, I know I have the worst sweet tooth out of all of us but I didn’t do it!”

“That does _not_ sound compelling at all,” Hirabayashi snorts, leaning back on his haunches and watching the proceedings with the sort of wry amusement uniquely reserved for Ieyasu and Ieyasu alone, “When you’re trying to convince someone that you didn’t do it, you might want to stop hiding first because it only makes you look guilty.”

Shimizu gently pries Ieyasu’s fingers off her shirt and says, _Sorry, Ieyasu-san. This is on you._

“Oh come on!” Yawara makes a swipe at him that Ieyasu avoids by clumsily rolling back, hands flailing uncontrollably in the air, “Wait - I swear to god it wasn’t me!”

“Then why are you _running_.” Yawara hisses, lunging for Ieyasu’s neck again. 

“Because if I don’t, then I’ll die before I can even prove my innocence!” He screeches, pulling himself up and making another attempt to run for it, only to trip on Hirabayshi’s outstretched legs. 

The only reason why he doesn’t fall is because Yawara snatches him by the collar before he could.

“Prove it then,” Yawara growls, lifting Ieyasu until they were face-to-face, “Prove it and maybe I’ll spare you.”

“That sounds so fucking metal.” Ryuko whispers. Hirabayashi and Shimizu nod in agreement.

Ieyasu squirms in Yawara’s hold, eyes flitting from corner to corner and avoiding Yawara’s intensity like his life depended on it. Which it kind of did. He then slumps, conceding with a pained grimace, “You won’t believe me even if I tell you.”

“Please, we don’t believe you _now_ ,” Hirabayashi comments, raising an eyebrow, “Honestly, try your worst.”

Shimizu giggles and Ryuko bursts out into peals of deafening laughter.

Ieyasu grumbles but he doesn’t move to dislodge Yawara’s hold on his shirt. He looks up at the ceiling, purses his lips and then says, “I saw a kid.”

“A kid?” Ryuko parrots, wiping the tears at the corner of her eyes, “Ieyasu, did you hit your head or what?”

“I was kind of hoping I did,” He says, shivering, “It was - I was up late a few nights ago because I couldn’t sleep so I went down to the kitchen to boil myself some of Yoichi’s leaf juice - which I’m pretty sure is _pure_ drugs no matter what he says but like,” He gulps here and seems to go paler even more than he already was, “I - I heard rummaging. In the cupboards. And then I saw him.”

Yawara looks less murderous and more curious now. Sure, Ieyasu was prone to spouting the worst bullshit they’d ever heard of but that’s the thing - he’s a terrible liar. And at the moment, Ieyasu was definitely not lying.

“It was a boy. With bandages wrapped around his eyes. Like - like he’d just gotten out of surgery or an accident or _something_. And he was bent over Yawara’s kikufuku like he was starving,” Yawara’s grip on Ieyasu’s clothes loosened until Ieyasu was on the ground, curled up at the foot of the sofa looking like he’d just seen a ghost, “I thought I was hallucinating. Or dreaming. He turned to look at me before he could even know I was there and when I blinked, he was suddenly _gone_.” 

Hirabayshi’s face was dubious but Shimizu’s own rapidly goes ashen.

“I know it sounds crazy but I swear I’m not making this up,” Ieyasu says, lips quivering, “And I didn’t say anything because honestly? Who would even believe me if I tell them that our dorms are _haunted?”_

* * *

“Those are some really nasty burns.”

Touya flinches, eyes snapping to the sudden voice that cuts into his self-imposed quietude. He hunches into himself, not taking his gaze off the other boy.

“Kikufuku?” The boy asks, offering him a small bag of what appeared to be was mochi, “It’s from Kikusuian. Edamame and cream,” He leans in slightly and Touya blinks at the blindfold over his eyes. Huh. Weird, “It’s their best flavour!”

Eyeing him warily, Touya asks, “Who are you?”

The child plops another mochi in his mouth, cheeks expanding like a chipmunk as he chews, before he tilts his head. His powdered covered lips stretches into a weird smile.

“I’m a man of many titles.” He declares solemnly, pulling back from Touya’s personal space. He hadn’t even realised that he’d gotten close enough to him until he was practically nose-to-nose with a stranger. Touya tries not to think too hard about that.

Squirming, he tells him, “You’re like, four. And younger than me.”

The blindfolded child purses his mouth into a pout, hands flying to his hips almost chidingly, “Excuse you, I’m _six_. And also the strongest.”

Touya snorts in disbelief. If he was the strongest, then Touya was the favourite child.

“All Might’s stronger than you. My _dad’s_ stronger than you,” He thinks about his newly born brother, a perfect split between his mother and his father, and feels his chest tighten, “You’re not as strong as you think you are.”

The other boy tilts his head, regarding Touya with a pensive look before he shrugs, lips still stuck into that weird smile.

“They’re only human,” He says, swinging back and forth on the balls of his feet. Touya rolls his eyes, because _you don’t need to state the obvious dummie_ , he thinks, before the other boy continues, tone as light and chirpy as a festival bell, “Humans are easy to kill. Easier than things you can’t see.”

_What_.

Touya freezes, thoughts screeching to a halt as he stares at the other in shock - in _fear_.

“They’re not infallible,” The boy says, and Touya doesn’t know if it’s the pain or the fear but he swears that there was an odd tune in between his syllables, ”And they’re not untouchable.“

Behind him, the sun starts to set, slowly casting them into the shadows. Touya catches a glow of blue hiding from underneath the fabric covering the other’s eyes.

“But _me_?”

The wind picks up the few stray leaves on the ground. They caress Touya’s cheeks and leave small kisses where the bandages and gauzes are taped onto his skin.

And then they stop, floating before they could touch the other boy, repelled by something that _Touya cannot see_.

He giggles and the sound sends a sudden shiver down Touya’s spine.

“Nothing can touch me,” He says, teeth sharpened into a point, “Nothing can _kill me_.”

That smile never left his face once. Touya feels his heart stopping and restarting within the span of a few seconds.

Then, like he hadn’t just threatened All Might, hadn’t just told him that his father could easily die, he shakes the bag in his hands again and says genially;

“Kikufuku?”

  
  


* * *

“Did you make a new friend, Satoru?”

Satoru watches as the red-haired boy stumbles away from him, hastily making his retreat without even saying goodbye. He ignores Satoru’s wave and doesn’t look back once. How disappointing, he giggles to himself. He’ll have to try harder next time.

Turning back to his guardian, Satoru watches as Shinya-nii hikes Kakashi up his hips. Kakashi only makes a soft noise before he’s back to napping, face buried in their brother's neck.

Kakashi is lazy and craves physical attention like no one else. Satoru thinks it’s cute.

“Yeah!” He says, grinning up at Shinya-nii, “I didn’t catch his name because he needed to go home soon before his dad worries. I think I’ll see him again soon though!”

Shinya-nii smiles at him from underneath his mask. He sets his free hand down on Satoru’s head and pets him affectionately.

“I’m glad. Maybe next time we go out, Kakashi can join you. _When he’s not being lazy.”_

Kakashi snuffles and Satoru and Shinya share a look of amusement.

* * *

_”By the way, where did you get the sweets?”_

_”Oh! Someone was nice enough to leave them in the kitchen!”_

_”No one saw you right? Shinya-niisan hasn’t told anyone we’re staying with them at the dorms yet.”_

_”Hmmmm, there was one dude I think. But he seemed pretty out of it.”_

_Kakashi shrugs, “If you’re sure.”_

**Notes for the Chapter:**

> Yawara Chatora is Tiger and Ryuko Tsuchikawa is Pixiebob! The rest of them are just random OCs and also for the sake of this fic, UA is already a boarding school! 
> 
> Satoru is criminally insane and Kakashi’s too tired to give a fuck lol.


End file.
